Home > Hollow Metal Doors > Hollow Metal Door Information and Resources > What Is The R Value For Hollow Metal Doors?

What Is The R Value For A Hollow Metal Door?

If you are in the market for a door or window, you may have heard the term or specification of an R value. In this article we explore what an R Value is for a hollow metal door.

Resistance To Heat

The R value for a hollow metal door is a measure of how well the door is able to resist heat, specifically the movement or transfer of heat. An easy way to remember the purpose of the R value, is to remember that the "R" stands for resistance. As a general rule of thumb, the higher the R value the better the hollow metal door can stop the transfer of heat. In contrast, a low R value would indicate the hollow metal door is not able to resist heat as well.

Why Is The R Value Important To Hollow Metal Doors?

How well a hollow metal door resists the movement of heat is very important in any building, especially if the hollow metal door is an exterior door. If you look at a commercial building, there are many components that help resist the transfer of heat including insulation, siding, roofing material, etc. All these components have special properties to help resist the transfer of heat. In the Summer, the building tries to retain the cool temperature inside, while keeping out the hot Summer air. In the Winter, the building tries to retain the heat inside, while keeping out the Cold Winter air. Having the proper building materials which resist the transfer of heat, will keep the building cool in the Summer and warm in the Winter. Doors and windows are extremely important components, since having a low R value window or door, could cost your building serious energy savings. A high R value for a hollow metal door will signify that the hollow metal door is suitable for an exterior door application and will be efficient at resisting the transfer of heat.

Factors Affecting R Values In Hollow Metal Doors

Door Thickness

One of the most common factors among hollow metal doors which affects the R value is the door thickness. Inherently, the thicker the hollow metal door, the better it is at resisting the movement of heat, and the higher the R value. Most commercial hollow metal doors are 1-3/4" thick, however there are models which are only 1-3/8" thick. A 1-3/4" thick hollow metal door will have a higher R value than a 1-3/8" thick hollow metal door.

Core Type

The biggest R value factor among hollow metal doors is the core type. Although, referred to as "hollow" metal doors, all hollow metal doors actually have some type of insulated core. Core types vary depending on the hollow metal door application. The two standard core types for hollow metal doors used on 99% of installations are a polystyrene foam core or a honeycomb cardboard core.

Polystyrene Core Vs. Honeycomb Core

A hollow metal door insulated with a polystyrene foam core will typically have an R value ranging from 2.4 to 2.8. While a honeycomb cardboard core can have an operating R value ranging from 1.7 to 1.9. As a result, polystyrene core hollow metal doors are used for both exterior or interior door applications, while honeycomb core hollow metal doors are primarily used for interior door applications.



Glass Window Lites

Another factor which can affect the R value of a hollow metal door is the amount of glass used on the door. Many hollow metal doors feature a vision lite, or glass window built into the door. Depending on how much glass surface area there is and the type of glass, this can affect the R value of the hollow metal door.



Conclusion

When you are in need of a hollow metal door with a great R value we recommend Patriot hollow metal steel doors. Our polystyrene core doors are energy efficient and durable. Used on commercial buildings nationwide, we offer both Fire Rated door assemblies and non-fire rated door assemblies. Patriot hollow metal doors are still manufactured in the USA. Shop today and receive FREE freight to your job site or preferred ship to location.




DISCLAIMER: INFORMATION PROVIDED THROUGH THIS SITE IS PROVIDED TO YOU AS IS WITHOUT ANY EXPRESS REPRESENTATIONS OR WARRANTIES OF ANY KIND, AND WE MAKE NO REPRESENTATION OR WARRANTY THAT THIS SITE (OR ANY INFORMATION PROVIDED IN RESPONSE TO YOUR INQUIRY), WILL BE ACCURATE, COMPLETE, OR ERROR-FREE. YOU AGREE THAT YOU MUST EVALUATE ALL INFORMATION AND RESPONSES, AND THAT YOU BEAR ALL RISKS ASSOCIATED WITH, THE USE OF THIS SITE, INCLUDING ANY RELIANCE ON THE ACCURACY,COMPLETENESS, OR USEFULNESS OF ANY INFORMATION OR MATERIALS MADE AVAILABLE THROUGH THIS SITE.